Raman study of a highly altered basalt -- AKB
igneous mineralogy, alteration products, & a microorganism
| A Martian analog rock, a 1.1 billion-year-old Keweenawan basalt (AKB). This rock is a highly altered basalt found in a creek. It has a fine-grained reddish matrix with small "clots" of a grayish-green clay mineral and coarse amygdules filled with light-colored minerals. Two surfaces of this rock are studied: | |
 |
 |
| heavily altered original surface, with surface relief of several mm. | roughly cut flat surface , unpolished. |
Mineral phases found in this rock:
 |
 |
 |
| The dark red matrix of the altered basalt yielded spectra of hematite (alpha-Fe2O3), plagioclase, saponite, and pyroxene. | The mineral phases inside the large, white amygdules are mainly calcite (CaCO3) and thomsonite (a type of zeolite). | some rare phases -- microorganism, anatase, quartz, and K-feldspar |
Mineral distributions and mineral proportions:
| Successive Raman spectra along two traverses cross from the matrix to amygdules and back. | Mineral modes obtained based on automated traverses on the original and sawn surfaces | |
 |
 |
 |
| Compare the two linear traverses, one with focus adjustment at each point, one without. Basic mineral distributions are the same. | Mineral modes obtained from the original surface | Mineral modes obtained from the sawn surface |
Reference:
Wang A., Jolliff B. L., Haskin L. A., “Raman spectroscopic characterization of
a highly weathered basalt – igneous mineralogy, alteration products, and a
bug”, Twenty-ninth Lunar and Planetary Science Conference, 1998.
Wang A., Jolliff, B.L., and Haskin L.A. (1999) Raman spectroscopic
characterization of a highly weathered basalt: igneous mineralogy, alteration
products, and a microorganism, J. Geophys. Res., 104, 27067 -27077.
[ lunar_sample ] [ point_count ] [ zagami ] [ akb ] [ oxides1 ] [ calib_rock ] [ grain_size ] [ mojave_rocks ] [ cored_samples ] [ sulf_carbonates ] [ sa chert ] [ pyroxene ] [ phyllosilicate ] [ ocean clays ] [ los Angeles ] [ fido2001 rocks ] [ eeta79001 ] [ alba_spores ] [ lichen ] [ earth_life ] [ oxides2 ] [ feldspar ] [ alt_olivine ]
